But if inventions have increased man's power over nature very much, then the real value of money is better measured for some purposes in labour than in commodities.

In the absence of any short term in common use to represent all desirable things, or things that satisfy human wants, we may use the term Goods for that purpose.

All labour is directed towards producing some effect.

Producer's Surplus is a convenient name for the genus of which the rent of land is the leading species.

It is common to distinguish necessaries, comforts, and luxuries; the first class including all things required to meet wants which must be satisfied, while the latter consist of things that meet wants of a less urgent character.

And very often the influence exerted on a person's character by the amount of his income is hardly less, if it is less, than that exerted by the way in which it is earned.

Consumption may be regarded as negative production.